The present invention relates to vehicle simulation systems, and more particularly to vehicle simulation systems with image systems that simulate a head-up display (xe2x80x9cHUDxe2x80x9d).
Vehicle simulation systems, such as flight simulator systems, are often used to train operators of such vehicles. Typically in such simulators the trainee views a simulated outside environment scene (called OTW, for xe2x80x9cout the windowxe2x80x9d) projected onto a screen by an image projector.
In real vehicles, especially aircraft, a head up display may be provided which projects information (xe2x80x9csymbologyxe2x80x9d) about targets, such as distance or speed, or a variety of other types of information, onto a combiner or beamsplitter positioned in front of the operator or pilot. The pilot looks through the combiner at the outside environment, and the head-up display optics keep the symbology information collimated and superposed from the operator""s viewpoint over the associated targets or other objects outside the vehicle to which the symbology relates.
In the simplest HUD simulators, a dummy combiner is provided which is clear, and a HUD visual field containing the symbology is projected on the viewing screen together with the OTW scene. In such a system, the symbology remains superposed and collimated with the visible scene that it relates to because both the visual object and the symbology are projected at the same location on the screen. However, the combined HUD/OTW scene is fully visible from any angle and position in the simulated cockpit. This means that the pilot can see the symbology even when looking around the combiner, which would not be possible in a real vehicle.
It is therefore an object of the present invention to provide more realistic vehicle simulation systems with a simulated HUD display.
In one embodiment, a vehicle simulation system includes an image system with one or more projectors which project a scene comprising a simulated OTW scene and a simulated HUD symbology field, with the HUD symbology collimated and superposed with the objects in the simulated OTW scene. A dummy combiner structure is positioned so that the user can view the scene with the superposed symbology through it. A filtering structure is supported laterally outward of the combiner structure. This filtering structure permits the OTW scene to be seen through it, but does not permit the light of the symbology to pass therethrough. This prevents the user from viewing the symbology through the filtering structure, thereby reducing the possibility of viewing of the HUD symbology except through the dummy combiner.
In accordance with an aspect of the invention, the filtering structure has characteristics of a notch filter, and the HUD symbology light has a wavelength which is notched out by said filter.
In another embodiment of the present invention, the filtering structure has characteristics of a polarization filter, and the HUD symbology is projected with conflicting polarization so as to be blocked by said filter.
In accordance with still another aspect of the present invention, the HUD symbology is projected only intermittently, and the filtering structure has characteristics of a time-varied filter such that the filter is opaque when the HUD symbology is present.
The above, as well as further features of the invention and advantages thereof, will be apparent in the following detailed description of certain advantageous embodiments which is to be read in connection with the accompanying drawings forming a part hereof, and wherein corresponding parts and components are identified by the same reference numerals in the several views of the drawings.